Certain gas turbine engines are mounted to the pylon via thrust links attached to the core of the engine, such as the Trent 500 of Rolls-Royce plc, shown in FIG. 1. These arrangements employ only one vee-groove attachment feature to transfer thrust reverser (TRU) axial load into the engine core. The vee-groove itself is disposed around the outside of a fan casing and cooperates with a vee-blade feature on a conventional C-duct, thereby securing the TRU to the engine. This vee-groove is positioned at the rear of the rear fancase. The TRU axial load is transferred to the thrust links via an annular array of fan outlet guide vanes (OGV), through an OGV twin plane support and into the core of the engine. One problem of this arrangement is the high bending loads applied through the OGV, which in turn causes high bending stresses through the engine core. Notably the load path from the outer vee-groove is tortuous and thus the structure is required to be strong and therefore heavy. In particular, the OGV twin plane supports carry substantial bending and axial loads and are significantly heavy. Furthermore, clearance gaps between compressor and turbine blades and their casings must be increased to accommodate the core engine bending deflections and therefore the engine does not operate as efficiently as possible.
Other gas turbine engines, such as the Trent 800 of Rolls-Royce plc, shown in FIG. 2, employ a second and radially inner vee-groove. However, this arrangement is only possible as there is no pylon core mounting arrangement, which would otherwise obstruct the inner vee-groove.
A more serious problem with both the prior art arrangements is that the vee-blade of the C-duct is relatively weak compared to the circumferential stiffness of the engine core vee-groove, which is usually annular. Thus it is possible for the vee-blade to deflect significantly so that bypass air may enter the C-duct structure itself causing serious structural damage bend. Such bending might also lead to disengagement the vee-groove and vee-blade, which is clearly undesirable.